Halogen-containing polymers, or halopolymers, are an important class of polymers and include for example, haloelastomers and haloplastics. Such halopolymers have good thermal stability and usefulness at relatively high temperatures, and toughness and flexibility at low temperatures. Some of these polymers are insoluble in a wide variety organic solvents, and are chemically inert. Some have extremely low dielectric loss and high dielectric-strength, and most have unique non-adhesive and low-friction properties.
Fluoroelastomers, particularly the copolymers of vinylidene fluoride with other ethylenically unsaturated halogenated monomers, such as hexafluoropropene, have utility in high temperature applications, such as seals, gaskets, and linings. In such applications, the shaped articles of fluoroelastomers are subject to exposure to aggressive or harsh environments such as solvents, lubricants, oxidizing or reducing conditions, and high temperature differentials.
A major drawback to many applications of shaped articles, such as seals, made of such fluoroelastomers has been their inability to satisfactorily function at low and high temperatures. At temperatures only slightly below 0.degree. C., the articles become stiff and brittle, and fail to perform satisfactorily. Many fluoroelastomers also exhibit a tendency to thermally degrade and structurally break down, losing their elastomeric nature after being exposed to high temperatures as well as repetitive large temperature differentials. Many fluoroelastomers also break down after long periods of exposure to harsh chemicals, such as solvents and lubricants, and to oxidizing or reducing conditions.
In particular sealing environments, the environment is harsh in experiencing large temperature differentials, from low to high temperatures, prolonged exposure to harsh chemicals, such as solvents, fuels and lubricants, and other harsh environmental conditions such as oxidation and reduction conditions. It is possible to find materials to address one of these environmental properties, such as a material that seals adequately in a statically cold environment, but it is very rare to find materials for seals that can withstand all of these harsh conditions.
There is a need for an elastomeric material having the ability to maintain flexibility, toughness and compressive strength after extended exposure to high temperature, low temperature and temperature differentials, to harsh chemical environments and to oxidation and reduction environments so as to be able to perform as a seal over an extended period of time in such severe environments encountered for sealing in areas such as engines, as well as aerospace, aeronautical and oceanographic fields. Such material should also be useful in preparing composite articles such as vacuum-type and pressure-type seals.
Conventional fluoroelastomers can be fabricated into automotive engine oil seals, fuel system components, such as fuel line hoses and o-ring seals, and drive train seals. Smaller, hotter-running automotive engines, modern fuel blends, and aggressive oil additives and other chemical substances used in operating the engines have made fluoroelastomers the polymers of choice for a host of elastomeric engine components where reliable sealing is required and of environmental concern.
Fluoroelastomers have also been utilized in other industries, including seals used in drilling equipment, seals in the aviation industry, such as in fuel tanks and window seals, and in the aerospace industry.
Commercially available fluoroelastomers, such as the illustrative polymers described above, are sold, for example, under the trademarks "AFLAS", "FLUOREL" and "VITON". Some of these are cross-linked with aromatic polyhydroxy compounds, such as bisphenols, which are compounded with the elastomer gum along with a curing accelerator, such as a quaternary phosphonium salt, and acid acceptors, such as magnesium oxide and calcium hydroxide. Such fluoroelastomers are set forth in U.S. Pat. No. 4,287,320 to Kolb. U.S. Pat. Nos. 4,035,565 to Apotheker et al. and 4,450,263 to West describe bromine-containing, peroxide-curable fluoroelastomers.
Several general types of fluorinated ethers have also been described in the literature. One type is characterized by one of several homopolymeric segments or blocks of repeating units of the formula--CF(CF.sub.3)CF.sub.2 --O-- and made from hexafluoropropylene epoxide as set forth in U.S. Pat. No. 3,250,807 to Fritz et al. Another type of fluoropolymer disclosed in U.S. Pat. No. 5,125,599 to Warnell contains blocks of repeating units of the formula --CF.sub.2 CF.sub.2 --O-- and is made from tetrafluoroethylene epoxide. Others, made by reacting oxygen with tetrafiuoroethylene or hexafluoropropylene, are characterized by backbones of repeating --CF.sub.2 O-- units as set forth in U.S. Pat. No. 3,392,097 to Carraro et al., or --CF(CF.sub.3)CF.sub.2 O-- units as set forth in U.S. Pat. No. 3,442,942 to Sianesi et al., or, in addition to either of these units, units of a formula --CF(CF.sub.3)O-- as set forth in U.S. Pat. No. 3,699,145 to Sianesi et al., or a backbone consisting of randomly distributed --CF.sub.2 O-- and --CF.sub.2 CF.sub.2 O-- units as set forth in U.S. Pat. No. 3,715,378 to Sianesi et al., or a backbone made up of --CF(CF.sub.3)CF.sub.2 O-- and --CF.sub.2 CF.sub.2 O-- units and, optionally, --CF(CF.sub.3)O-- units. Another type of fluorinated ether described in U.S. Pat. Nos. 3,504,411 to Rice and 3,849,594 to Mitsch et al. contains backbone units of the formula --(CF.sub.2).sub.a O(CF.sub.2).sub.b -- made by photopolymerization.
U.S. Pat. Nos. 3,810,874 to Mitsch et al. and 4,094,911 to Mitsch et al. disclose poly(perfluoroalkylene oxides)terminated with polymerizable functional groups which can be polymerized to prepare certain polymers, e.g., polyurethanes, having low glass transition temperatures and low-temperature flexibility. U.S. Pat. No. 3,810,875 to Rice et al. discloses use of poly(perfluoroalkylene oxide) peroxides with ethylenically unsaturated monomers in making block copolymers having good low-temperature flexibility. Fluorinated ethers with non-functional terminal moieties are sold under the trademarks "KRYTOX" and "FOMBLIN" for use as vacuum pump fluids.
U.S. Pat. No. 4,810,760 to Strepparola et al. describes compositions of fluoroelastomer cross-linked with dihydroxypolyfluoroethers. The dihydroxypolyfluoroethers contain either branched moieties or are random copolymers containing --CF.sub.2 O-- repeating units, or contain partially fluorinated repeating units. When used to cross-link fluoroelastomers, the fluorinated ethers are said to yield materials with improved heat stability and greater resistance to compression set. U.S. Pat. No. 4,894,418 to Strepparola et al. discloses compositions of fluoroelastomers comprising, as a processing coadjuvant, a mono- or dihydroxypolyfluoroether. These mono- or dihydroxypolyfluoroethers have similar structures to those disclosed in U.S. Pat. No. 4,810,760 to Strepparola et al. The addition of these mono- or dihydroxypolyfluoroethers to conventional vulcanizable fluoroelastomer compositions is said to improve the processability of the resulting mixture and the low temperature brittle point of the cured mixture.
U.S. Pat. No. 3,632,788 to Stivers et al. describes fluoro-olefinic elastomeric formulations with improved low temperature flexibility and softness. The improved properties are imparted by the incorporation of one or more low melting low molecular weight, polar, fluoroaliphatic compounds. U.S. Pat. No. 5,026,786 to Marchionni et al. describes a process for the manufacture of certain perfluoropolyethers. These perfluoropolyethers comprise randomly distributed perfluoroxyalkylene units. These perfluoropolyethers are said to improve the extrudability of elastomer compositions and to decrease the adhesion of vulcanized articles to molds. U.S. Pat. No. 4,278,776 to Mauro et al. discloses vulcanizable mixes based on fluoroelastomers and which comprise at least one fluorinated polyamide. Certain perfluoropolyethers are said to improve the low temperature properties of the vulcanizates.
The above-described fluoroelastomer compositions are comprised of organic components alone.
Ceramer type compositions, which are compositions containing organic and inorganic components, and processes for the preparation thereof are described in: U.S. Pat. Nos. 5,116,703 to Badesha et al.; 5,013,624 to Yu; 4,917,980 to Badesha et al.; 4,400,434 to Santoso; 4,051,100 to Bjerk et al.; 3,775,163 to Marzocchi; 3,663,842 to Miller; 4,743,503 to Lin et al.; and 5,196,228 to Kirby et al.; Lentz et al., "Filler Treatments for Thermally Conductive Silicone Elastomers", Xerox Disclosure Journal, Vol. 5, No. 5, pp. 493-94 (September/October 1980); Wilkes et al., "Ceramers: Hybrid Materials Incorporating Polymeric/Oligomeric Species into Inorganic Classes Utilizing a Sol-Gel Approach", ACS Polymer Reprints, Vol. 26 (2), pp. 300-301 (1985). The disclosures of these references are incorporated herein by reference.
U.S. patent application Ser. No. 08/044,870 to Badesha et al., the disclosure of which is incorporated herein by reference, discloses a fuser member comprising a supporting substrate and a layer comprised of integral interpenetrating networks of haloelastomer and silica, and a composition comprising substantially uniform integral interpenetrating networks of haloelastomer and silica.
U.S. patent application Ser. No. 08/044,860 to Badesha et al., the disclosure of which is incorporated herein by reference, describes a fuser member comprising a supporting substrate and a layer comprised of integral interpenetrating networks of haloelastomer, silica, and polyorganosiloxane, and a composition comprising substantially uniform integral interpenetrating networks of haloelastomer, silica, and polyorganosiloxane.
U.S. patent applications Ser. Nos. 08/141,748 and 08/141,747 to Badesha et al., the disclosures of which are incorporated herein by reference, disclose intermediate transfer component coating/articles of titamer and grafted titamer and ceramer and grafted ceramer.
U.S. patent application Ser. No. 08/035,023 to Badesha et al., the disclosure of which is incorporated herein by reference, describes an intermediate toner transfer component comprised of a substrate and thereover a coating/article comprised of a volume grafted elastomer, which is a substantially uniform integral interpenetrating network of a hybrid composition of a fluoroelastomer and a polyorganosiloxane. The volume graft is formed by dehydrofluorination of the fluoroelastomer by a nucleophilic dehydrofluorinating agent, followed by addition polymerization by the addition of an alkene or alkyne functionally terminated polyorganosiloxane and a polymerization initiator.
U.S. patent application Ser. No. 08/083,922 to Badesha, the disclosure of which is incorporated herein by reference, describes a fuser member comprising a supporting substrate and a layer comprised of integral interpenetrating networks of haloelastomer and titanium oxide, and a composition comprising substantially uniform integral interpenetrating networks of haloelastomer and titanium oxide.
U.S. patent application Ser. No. 08/084,882 to Badesha, the disclosure of which is incorporated herein by reference, sets forth a fuser member comprising a supporting substrate and a layer comprised of integral interpenetrating networks of haloelastomer, titanium oxide, and polyorganosiloxane, and a composition comprising substantially uniform integral interpenetrating networks of haloelastomer, titanium oxide, and polyorganosiloxane.